Arduino UNO restarting alone [closed]

Good afternoon, I have an arduino UNO, and a GSM ICONSAT 1.1 shield here, I was working normally with both, receiving and sending SMSs, however when I added a SD Card shield to generate a datalogger the arduino keeps restarting itself. So I just tested the SD Card, and it worked perfectly. But the GSM shield and the Shield SD Card do not work together. Does anyone know why?

Serial Monitor Image:

CodeUsed: GitHub

Funny that if I comment on that part of the code:

myFile = SD.open("dados.txt", FILE_WRITE);
if (myFile){                                     
  Serial.print("Escrevendo em arquivo...");     //Escreve no arquivo
  myFile.println("hello SD Card Shield!");      //Teste de escrita

  myFile.close();                               //Fecha o arquivo
  Serial.println("Escrita finalizada");         //Informa escrita finalizada
}else{
  Serial.println("Erro ao abrir arquivo");      //Informa que há algum erro
}

The arduino does not restart, however, I can not write the data in the .txt file.